AGE AT CARDIO-METABOLIC DISEASE ONSET IN A COHORT OF MIDLIFE WOMEN: SYSTEMATIC EXCLUSION MISESTIMATES THE MAGNITUDE OF RACIAL DISPARITIES

Abstract Cohort studies of aging recruit participants at an age before most of the population experiences the study outcome, to document its natural history. The age of study commencement is usually based on “normative” aging among Whites. However, “weathering” can cause accelerated health declines in minoritized populations compared to Whites due to cumulative experience of multiple forms of marginalization. Thus, considering if weathering among minoritized individuals could affect selection into cohort studies is necessary to effectively estimate and understand racial/ethnic disparities in aging and disease. Using the Study of Women’s Health Across the Nation (SWAN), a multi-ethnic longitudinal cohort, and its cross-sectional screening survey, we examine the effects of selection on the racial/ethnic differences in the age of onset of 4 cardio-metabolic outcomes (hypertension, isolated systolic hypertension, insulin resistance and diabetes). Selection at study commencement (left truncation and left censoring) had greater effects on outcomes with earlier age at onset (hypertension) and right censoring had greater effects on outcomes with later onsets (metabolic). Full adjustment led to an average 20-year decrease in predicted median age of onset for all groups across the 4 outcomes and tended to decrease the predicted disparity in age at onset. However, significantly earlier onset of each outcome for Black and Hispanic women compared to Whites remained. Not considering the full extent of selection bias in cohort studies can misinform our understanding of aging and disease, especially for minoritized populations who have higher prevalence of these leading causes of morbidity and mortality earlier in life.

fore most of the population experiences the study outcome, to document its natural history. The age of study commencement is usually based on "normative" aging among Whites. However, "weathering" can cause accelerated health declines in minoritized populations compared to Whites due to cumulative experience of multiple forms of marginalization. Thus, considering if weathering among minoritized individuals could affect selection into cohort studies is necessary to effectively estimate and understand racial/ethnic disparities in aging and disease. Using the Study of Women's Health Across the Nation (SWAN), a multi-ethnic longitudinal cohort, and its cross-sectional screening survey, we examine the effects of selection on the racial/ethnic differences in the age of onset of 4 cardio-metabolic outcomes (hypertension, isolated systolic hypertension, insulin resistance and diabetes). Selection at study commencement (left truncation and left censoring) had greater effects on outcomes with earlier age at onset (hypertension) and right censoring had greater effects on outcomes with later onsets (metabolic). Full adjustment led to an average 20-year decrease in predicted median age of onset for all groups across the 4 outcomes and tended to decrease the predicted disparity in age at onset. However, significantly earlier onset of each outcome for Black and Hispanic women compared to Whites remained. Not considering the full extent of selection bias in cohort studies can misinform our understanding of aging and disease, especially for minoritized populations who have higher prevalence of these leading causes of morbidity and mortality earlier in life.

. National Institute for Nutrition and Health Chinese Center for Disease Control and Prevention, China, Beijing, China (People's Republic), 5. National Institute for Nutrition and Health Chinese Center for Disease Control and Prevention, Beijing, Beijing, China (People's Republic)
Introduction: Evidence suggests a positive association between muscle mass and cognitive impairment exists. Mid-upper arm muscle circumference (MUMC) is a simple measure that may provide prognostic information on cognitive status.
Methods: We included adults aged ≥55 years from the China Health and Nutrition Survey 1997-2018 with MUAC and triceps skinfold (TSF) measurements at each visit. Cognition was estimated based on a subset of the modified Telephone Interview for Cognitive Status (TICS, 0─27). Sexstratified linear mixed-effects models accounting for withinindividual and within-community correlation assessed the association between MUAC and the ratio of MUAC:TSF with TICS across age. We tested whether the rate of cognitive decline by age differed by quartiles of MUAC and MUAC:TSF in separate models. In cases of no statistical differences in cognitive declines by age, we tested whether overall cognitive function was associated with quartiles of MUAC and MUAC:TSF across all ages.
Results: Of 5,964 adults (53% female, age 62.4±6.4), mean MUAC was 26.6±3.74 and 26.2±3.9 cm, mean MUAC:TSF ratio was 2.9±1.6 and 1.94±1.1, and baseline TICS was 15.4±6.1 and 13.2±6.4 for men and women, respectively. MUAC was not associated with the rate of cognitive decline. Lower MUAC was associated with higher overall cognitive function scores for men (p=0.01) and women (p=0.05). For men and women there was no association between MUAC:TSF ratio and either cognitive decline or overall function.
Conclusion: MUMC can be a marker to predict overall cognitive function across this period in the lifecycle, Innovation in Aging, 2022, Vol. 6, No. S1